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d6c7428f RF |
1 | /* |
2 | * An I2C driver for the Intersil ISL 12022 | |
3 | * | |
4 | * Author: Roman Fietze <roman.fietze@telemotive.de> | |
5 | * | |
6 | * Based on the Philips PCF8563 RTC | |
7 | * by Alessandro Zummo <a.zummo@towertech.it>. | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU General Public License version | |
11 | * 2 as published by the Free Software Foundation. | |
12 | */ | |
13 | ||
14 | #include <linux/i2c.h> | |
15 | #include <linux/bcd.h> | |
16 | #include <linux/rtc.h> | |
17 | #include <linux/slab.h> | |
18 | ||
19 | #define DRV_VERSION "0.1" | |
20 | ||
21 | /* ISL register offsets */ | |
22 | #define ISL12022_REG_SC 0x00 | |
23 | #define ISL12022_REG_MN 0x01 | |
24 | #define ISL12022_REG_HR 0x02 | |
25 | #define ISL12022_REG_DT 0x03 | |
26 | #define ISL12022_REG_MO 0x04 | |
27 | #define ISL12022_REG_YR 0x05 | |
28 | #define ISL12022_REG_DW 0x06 | |
29 | ||
30 | #define ISL12022_REG_SR 0x07 | |
31 | #define ISL12022_REG_INT 0x08 | |
32 | ||
33 | /* ISL register bits */ | |
34 | #define ISL12022_HR_MIL (1 << 7) /* military or 24 hour time */ | |
35 | ||
36 | #define ISL12022_SR_LBAT85 (1 << 2) | |
37 | #define ISL12022_SR_LBAT75 (1 << 1) | |
38 | ||
39 | #define ISL12022_INT_WRTC (1 << 6) | |
40 | ||
41 | ||
42 | static struct i2c_driver isl12022_driver; | |
43 | ||
44 | struct isl12022 { | |
45 | struct rtc_device *rtc; | |
46 | ||
47 | bool write_enabled; /* true if write enable is set */ | |
48 | }; | |
49 | ||
50 | ||
51 | static int isl12022_read_regs(struct i2c_client *client, uint8_t reg, | |
52 | uint8_t *data, size_t n) | |
53 | { | |
54 | struct i2c_msg msgs[] = { | |
55 | { | |
56 | .addr = client->addr, | |
57 | .flags = 0, | |
58 | .len = 1, | |
59 | .buf = data | |
60 | }, /* setup read ptr */ | |
61 | { | |
62 | .addr = client->addr, | |
63 | .flags = I2C_M_RD, | |
64 | .len = n, | |
65 | .buf = data | |
66 | } | |
67 | }; | |
68 | ||
69 | int ret; | |
70 | ||
71 | data[0] = reg; | |
72 | ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); | |
73 | if (ret != ARRAY_SIZE(msgs)) { | |
74 | dev_err(&client->dev, "%s: read error, ret=%d\n", | |
75 | __func__, ret); | |
76 | return -EIO; | |
77 | } | |
78 | ||
79 | return 0; | |
80 | } | |
81 | ||
82 | ||
83 | static int isl12022_write_reg(struct i2c_client *client, | |
84 | uint8_t reg, uint8_t val) | |
85 | { | |
86 | uint8_t data[2] = { reg, val }; | |
87 | int err; | |
88 | ||
89 | err = i2c_master_send(client, data, sizeof(data)); | |
90 | if (err != sizeof(data)) { | |
91 | dev_err(&client->dev, | |
92 | "%s: err=%d addr=%02x, data=%02x\n", | |
93 | __func__, err, data[0], data[1]); | |
94 | return -EIO; | |
95 | } | |
96 | ||
97 | return 0; | |
98 | } | |
99 | ||
100 | ||
101 | /* | |
102 | * In the routines that deal directly with the isl12022 hardware, we use | |
103 | * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. | |
104 | */ | |
105 | static int isl12022_get_datetime(struct i2c_client *client, struct rtc_time *tm) | |
106 | { | |
107 | uint8_t buf[ISL12022_REG_INT + 1]; | |
108 | int ret; | |
109 | ||
110 | ret = isl12022_read_regs(client, ISL12022_REG_SC, buf, sizeof(buf)); | |
111 | if (ret) | |
112 | return ret; | |
113 | ||
114 | if (buf[ISL12022_REG_SR] & (ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75)) { | |
115 | dev_warn(&client->dev, | |
116 | "voltage dropped below %u%%, " | |
117 | "date and time is not reliable.\n", | |
118 | buf[ISL12022_REG_SR] & ISL12022_SR_LBAT85 ? 85 : 75); | |
119 | } | |
120 | ||
121 | dev_dbg(&client->dev, | |
122 | "%s: raw data is sec=%02x, min=%02x, hr=%02x, " | |
123 | "mday=%02x, mon=%02x, year=%02x, wday=%02x, " | |
124 | "sr=%02x, int=%02x", | |
125 | __func__, | |
126 | buf[ISL12022_REG_SC], | |
127 | buf[ISL12022_REG_MN], | |
128 | buf[ISL12022_REG_HR], | |
129 | buf[ISL12022_REG_DT], | |
130 | buf[ISL12022_REG_MO], | |
131 | buf[ISL12022_REG_YR], | |
132 | buf[ISL12022_REG_DW], | |
133 | buf[ISL12022_REG_SR], | |
134 | buf[ISL12022_REG_INT]); | |
135 | ||
136 | tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F); | |
137 | tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F); | |
138 | tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F); | |
139 | tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F); | |
140 | tm->tm_wday = buf[ISL12022_REG_DW] & 0x07; | |
141 | tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1; | |
142 | tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100; | |
143 | ||
144 | dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " | |
145 | "mday=%d, mon=%d, year=%d, wday=%d\n", | |
146 | __func__, | |
147 | tm->tm_sec, tm->tm_min, tm->tm_hour, | |
148 | tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); | |
149 | ||
150 | /* The clock can give out invalid datetime, but we cannot return | |
151 | * -EINVAL otherwise hwclock will refuse to set the time on bootup. */ | |
152 | if (rtc_valid_tm(tm) < 0) | |
153 | dev_err(&client->dev, "retrieved date and time is invalid.\n"); | |
154 | ||
155 | return 0; | |
156 | } | |
157 | ||
158 | static int isl12022_set_datetime(struct i2c_client *client, struct rtc_time *tm) | |
159 | { | |
160 | struct isl12022 *isl12022 = i2c_get_clientdata(client); | |
161 | size_t i; | |
162 | int ret; | |
163 | uint8_t buf[ISL12022_REG_DW + 1]; | |
164 | ||
165 | dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " | |
166 | "mday=%d, mon=%d, year=%d, wday=%d\n", | |
167 | __func__, | |
168 | tm->tm_sec, tm->tm_min, tm->tm_hour, | |
169 | tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); | |
170 | ||
171 | if (!isl12022->write_enabled) { | |
172 | ||
173 | ret = isl12022_read_regs(client, ISL12022_REG_INT, buf, 1); | |
174 | if (ret) | |
175 | return ret; | |
176 | ||
177 | /* Check if WRTC (write rtc enable) is set factory default is | |
178 | * 0 (not set) */ | |
179 | if (!(buf[0] & ISL12022_INT_WRTC)) { | |
180 | dev_info(&client->dev, | |
181 | "init write enable and 24 hour format\n"); | |
182 | ||
183 | /* Set the write enable bit. */ | |
184 | ret = isl12022_write_reg(client, | |
185 | ISL12022_REG_INT, | |
186 | buf[0] | ISL12022_INT_WRTC); | |
187 | if (ret) | |
188 | return ret; | |
189 | ||
190 | /* Write to any RTC register to start RTC, we use the | |
191 | * HR register, setting the MIL bit to use the 24 hour | |
192 | * format. */ | |
193 | ret = isl12022_read_regs(client, ISL12022_REG_HR, | |
194 | buf, 1); | |
195 | if (ret) | |
196 | return ret; | |
197 | ||
198 | ret = isl12022_write_reg(client, | |
199 | ISL12022_REG_HR, | |
200 | buf[0] | ISL12022_HR_MIL); | |
201 | if (ret) | |
202 | return ret; | |
203 | } | |
204 | ||
205 | isl12022->write_enabled = 1; | |
206 | } | |
207 | ||
208 | /* hours, minutes and seconds */ | |
209 | buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec); | |
210 | buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min); | |
211 | buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour); | |
212 | ||
213 | buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday); | |
214 | ||
215 | /* month, 1 - 12 */ | |
216 | buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1); | |
217 | ||
218 | /* year and century */ | |
219 | buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100); | |
220 | ||
221 | buf[ISL12022_REG_DW] = tm->tm_wday & 0x07; | |
222 | ||
223 | /* write register's data */ | |
224 | for (i = 0; i < ARRAY_SIZE(buf); i++) { | |
225 | ret = isl12022_write_reg(client, ISL12022_REG_SC + i, | |
226 | buf[ISL12022_REG_SC + i]); | |
227 | if (ret) | |
228 | return -EIO; | |
229 | }; | |
230 | ||
231 | return 0; | |
232 | } | |
233 | ||
234 | static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
235 | { | |
236 | return isl12022_get_datetime(to_i2c_client(dev), tm); | |
237 | } | |
238 | ||
239 | static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
240 | { | |
241 | return isl12022_set_datetime(to_i2c_client(dev), tm); | |
242 | } | |
243 | ||
244 | static const struct rtc_class_ops isl12022_rtc_ops = { | |
245 | .read_time = isl12022_rtc_read_time, | |
246 | .set_time = isl12022_rtc_set_time, | |
247 | }; | |
248 | ||
249 | static int isl12022_probe(struct i2c_client *client, | |
250 | const struct i2c_device_id *id) | |
251 | { | |
252 | struct isl12022 *isl12022; | |
253 | ||
254 | int ret = 0; | |
255 | ||
256 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) | |
257 | return -ENODEV; | |
258 | ||
259 | isl12022 = kzalloc(sizeof(struct isl12022), GFP_KERNEL); | |
260 | if (!isl12022) | |
261 | return -ENOMEM; | |
262 | ||
263 | dev_dbg(&client->dev, "chip found, driver version " DRV_VERSION "\n"); | |
264 | ||
265 | i2c_set_clientdata(client, isl12022); | |
266 | ||
267 | isl12022->rtc = rtc_device_register(isl12022_driver.driver.name, | |
268 | &client->dev, | |
269 | &isl12022_rtc_ops, | |
270 | THIS_MODULE); | |
271 | ||
272 | if (IS_ERR(isl12022->rtc)) { | |
273 | ret = PTR_ERR(isl12022->rtc); | |
274 | goto exit_kfree; | |
275 | } | |
276 | ||
277 | return 0; | |
278 | ||
279 | exit_kfree: | |
280 | kfree(isl12022); | |
281 | ||
282 | return ret; | |
283 | } | |
284 | ||
285 | static int isl12022_remove(struct i2c_client *client) | |
286 | { | |
287 | struct isl12022 *isl12022 = i2c_get_clientdata(client); | |
288 | ||
289 | rtc_device_unregister(isl12022->rtc); | |
290 | kfree(isl12022); | |
291 | ||
292 | return 0; | |
293 | } | |
294 | ||
295 | static const struct i2c_device_id isl12022_id[] = { | |
296 | { "isl12022", 0 }, | |
297 | { "rtc8564", 0 }, | |
298 | { } | |
299 | }; | |
300 | MODULE_DEVICE_TABLE(i2c, isl12022_id); | |
301 | ||
302 | static struct i2c_driver isl12022_driver = { | |
303 | .driver = { | |
304 | .name = "rtc-isl12022", | |
305 | }, | |
306 | .probe = isl12022_probe, | |
307 | .remove = isl12022_remove, | |
308 | .id_table = isl12022_id, | |
309 | }; | |
310 | ||
311 | static int __init isl12022_init(void) | |
312 | { | |
313 | return i2c_add_driver(&isl12022_driver); | |
314 | } | |
315 | ||
316 | static void __exit isl12022_exit(void) | |
317 | { | |
318 | i2c_del_driver(&isl12022_driver); | |
319 | } | |
320 | ||
321 | module_init(isl12022_init); | |
322 | module_exit(isl12022_exit); | |
323 | ||
324 | MODULE_AUTHOR("roman.fietze@telemotive.de"); | |
325 | MODULE_DESCRIPTION("ISL 12022 RTC driver"); | |
326 | MODULE_LICENSE("GPL"); | |
327 | MODULE_VERSION(DRV_VERSION); |